This invention relates in general to crushing machines and more particularly to a cone-type crusher and a bearing arrangement for such a crusher.
The typical cone-type rock crusher has a fixed conical surface that flares outwardly from a hopper, and located opposite to this surface is a conical crushing head which is mounted on an eccentric shaft. The arrangement is such that when the shaft revolves, the head undergoes a wobbling gyratory motion opposite the fixed conical surface, and as a consequence the space between any point on the fixed surface and the head continually expands and contracts. Thus, rock from the hopper will enter the space as it opens, and this rock is crushed as the space closes. Furthermore, the space tapers downwardly toward the periphery of the fixed conical surface so that the rock particles become progressively smaller as they move outwardly away from the hopper.
Since the rock is in effect wedged between the fixed conical surface and the crusher head as the head gyrates, heavy radial and thrust loads are imposed on the head, and these loads are transmitted to the eccentric shaft and to the frame of the machine through bearings. In the larger machines, the bearings take the form of cylindrical roller bearings oriented to accommodate both the radial and thrust loads. These bearing assemblies are in themselves quite massive, often having as many as six rows of cylindrical rollers. Moreover, they are especially constructed for such rock crushers, and as such are quite expensive. Inasmuch as they utilize cylindrical rollers at thrust locations they are incapable of providing pure rolling contact at these locations, so some skidding does occur along the thrust raceways, all to the detriment of the bearing. Furthermore, cylindrical roller bearings are incapable of being adjusted so that the wear in the bearings results in ever increasing lateral free motion for the head, a condition that is not desirable.
Some smaller machines utilize tapered roller bearings between the crusher head and the eccentric shaft, and likewise between the shaft and the machine frame, but present bearing arrangements of this nature are not altogether satisfactory. For example, while such bearings are capable of being adjusted against each other to remove all end and radial play, the adjustments are not easily made because of the size and orientation of the bearings. More specifically, the tapered rollers at some locations tend, by virtue of their own weight, to move away from a properly seated position with respect to their raceways, and as a consequence, it is difficult to bring them into a properly seated position. Also, tapered roller bearings when mounted in pairs are capable of taking thrust loading in both axial directions as well as radial loading, and therefore when compared with cylindrical roller bearings, fewer of them are needed for the crusher head and the eccentric shaft. However, the spread between the bearings of each pair must be relatively large to accommodate thrust couples, and this results in a machine of extended length.